ThinAir Geo

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isochrone

Generate travel-time or travel-distance reachability polygons from an origin. Supports multiple bands in one call, returning nested GeoJSON polygons.

Instructions

Generate travel-time or travel-distance reachability polygons from an origin. Pass MULTIPLE bands in one call — e.g. contours_minutes:[10,20,30] returns three nested polygons in a single response. Output is GeoJSON ready for Mapbox / Leaflet.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "isochrone"
  }
}

Input Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Apr 28, 2026

TDQS

B3.4/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations exist. Description notes output is GeoJSON and that multiple bands return nested polygons, but it does not disclose limits, authentication requirements, or the need for an origin parameter. The example parameter 'contours_minutes' is not in the schema, causing confusion.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Description is two sentences, front-loaded with the core purpose, and includes a concrete example. No wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Despite lack of schema, description omits how to specify the origin, valid parameter values, error handling, and other required inputs. Output format is covered but insufficient for a tool with implied parameters and no output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema is an empty object, so the description adds meaning by mentioning 'contours_minutes' and its usage. However, this creates inconsistency since the schema does not define any parameter. Baseline 3 adjusted for added information but with contradiction.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Description clearly states the tool generates travel-time or travel-distance reachability polygons from an origin. This is a specific verb+resource, and the tool is distinct from sibling tools like directions or geocode.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides an example of passing multiple bands but does not explicitly state when to use this tool versus alternatives or any exclusions. Usage context is implied but not directly addressed.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.